1. Technical Field
This invention generally relates to structures for manufacturing compost, and more particularly, this invention relates to a composting bin having a polyhedral-geodesic shape to facilitate optimum mixing of the compost and maximize microbial activity.
2. Background Art
Composting is the natural biological process by which organic waste is converted into soil constituents by microorganisms. Recently, there has been a large amount of interest in composting as an alternative means of dealing with organic household and yard wastes due to the high cost, limited availability and potential environmental impact of traditional landfill waste disposal. The emphasis on composting results from the desire to reduce the amount of waste deposited in landfills or incinerated in waste processing plants.
Consequently, several devices, methods and catalysts have been developed to improve composting efficiency and make the process more convenient. In general, the efficiency of the composting process is controlled by the nutrient content of the waste and the composting environment. The present invention is concerned with the composting environment.
Because composting is an aerobic process it is critical that the waste mass or "heap" receive an adequate supply of oxygen. In fact, oxygen is the single most important limiting factor in the rate of compost production, all other things being equal. Since the optimal water content is approximately 45% to 60%, excess water which would tend to suffocate the aerobic process must be drained away. Additionally, the waste mass should be agitated to ensure that fresh air is available to the bacteria. The later requirement poses the biggest problem for home composters as the shear bulk of the waste mass is cumbersome when contained in a bin and unruly when uncontained. Depending on the moisture content of the waste mass, the entire pile should be turned at least once every other day and as much as twice a day to ensure the maximum rate of compost production.
U.S. Pat. No. 4,797,367 to J. A. Pinder describes an aerobic domestic composting device which utilizes an air diffusing device in connection with a plastic bag lined drum. The primary objective of this device being to promote aeration of the composting heap without allowing insects and the like from infesting the heap.
U.S. Pat. No. 3,837,810 to A. Z. Richards and L. S. Madsen describes a rotatable composter which is essentially a rectangular bin rotatably mounted about horizontally disposed axis. The bin is selectively rotated to agitate and aerate the composting heap. Stationary lifters or lugs, disposed on the central axle, act to both aerate and agitate the heap.
U.S. Pat. No. 4,687,645 to C. D. Harvey describes a composting apparatus which uses a 55 gallon drum-like container having a horizontal transverse axis to facilitate end for end rotation of the drum. A perforated pipe is provided along the longitudinal axis of the drum to promote aeration of the composting heap.
U.S. Pat. No. 3,934,999 to H. R. Meier describes the use of a plastic bag as a composting container which permits agitation of the heap by "fluffing" or kicking the bag. Perforations are provided in the side walls of the bag to promote aeration of the heap. The primary drawback to this device is the necessary size limitation due to the lack of structural integrity of the flexible bag. In order to maintain a self generating compost heap in colder climates, it is generally accepted that the heap mass should have a volume of at least a cubic yard of material. Also, because the volume of compost produced is anywhere from 20% to 30% of the original volume of waste material, a 30 gallon plastic bag is only capable of producing a few cubic feet of compost at the most. It can easily be appreciated that in order to construct a flexible plastic bag having a larger volume, the necessary thickness of the side walls of the bag would defeat the objects of the invention. Simply limiting the thickness of the container to that necessary to maintain a flexible plastic bag would result in the bag tearing, not to mention the inability of a single person to manipulate the heap. Additionally, as the size of the heap is increased, it becomes more important to provide some interior means to agitate the heap. Finally, it is evident that the plastic bag is difficult to roll and transport.
It is therefore an object of the present invention to provide a composting container which enables a single person to frequently, easily and conveniently agitate its contents and thereby facilitate the composting rate. It is a further object of this invention to provide a composting container which is easy to assemble. It is a further object of this invention to provide a composting container which can be loaded and unloaded with a minimum effort expended. It is a further object of this invention to provide a composting container which is easy to clean and which requires minimal maintenance.